[PATCH 4.18 76/79] x86/mm/pat: Make set_memory_np() L1TF safe

From: Greg Kroah-Hartman
Date: Tue Aug 14 2018 - 13:28:09 EST


4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

set_memory_np() is used to mark kernel mappings not present, but it has
it's own open coded mechanism which does not have the L1TF protection of
inverting the address bits.

Replace the open coded PTE manipulation with the L1TF protecting low level
PTE routines.

Passes the CPA self test.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/mm/pageattr.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1014,8 +1014,8 @@ static long populate_pmd(struct cpa_data

pmd = pmd_offset(pud, start);

- set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
- massage_pgprot(pmd_pgprot)));
+ set_pmd(pmd, pmd_mkhuge(pfn_pmd(cpa->pfn,
+ canon_pgprot(pmd_pgprot))));

start += PMD_SIZE;
cpa->pfn += PMD_SIZE >> PAGE_SHIFT;
@@ -1087,8 +1087,8 @@ static int populate_pud(struct cpa_data
* Map everything starting from the Gb boundary, possibly with 1G pages
*/
while (boot_cpu_has(X86_FEATURE_GBPAGES) && end - start >= PUD_SIZE) {
- set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
- massage_pgprot(pud_pgprot)));
+ set_pud(pud, pud_mkhuge(pfn_pud(cpa->pfn,
+ canon_pgprot(pud_pgprot))));

start += PUD_SIZE;
cpa->pfn += PUD_SIZE >> PAGE_SHIFT;